One of my favorite parts of doing Windows Presentation Foundation (Code Named Avalon) presentations is showing off the Expression Interactive Designer (ie Sparkle)

This way cool tool makes creating XAML a breeze and lets you do it with very powerfull timeline capabalities (animations)

http://www.microsoft.com/downloads/details.aspx?FamilyID=ed9f5fb2-4cfc-4d2c-9af8-580d644e3d1d&DisplayLang=en&hash=TJF7SW9

Or go to downloads and serch for "Expression"